Green energy plan would turn sugar beets into biofuels

Share this:

The diagram shows the multiple processes involved in the proposed sugar beet-to-ethanol operation. The biorefinery could convert sugar beets into ethanol, as well as produce electricity, biogas, compressed natural gas and fertilizer, and would include a water treatment plant.

The vacant Spreckels sugar beet factory in Mendota may receive a green energy overhaul, as a group of former sugar beet farmers pursues a plan to transform the site into an advanced biorefinery using several high-tech processes to convert sugar beets into ethanol and other forms of energy.

The plant would convert San Joaquin Valley sugar beets into about 40 million gallons of ethanol annually, and be the first operation of its kind in the United States.

Farmer-investors, universities and other partners began the process in 2008, the same year that the Mendota sugar beet factory closed, leaving only an Imperial Valley plant to carry on the state”s tradition of sugar beet processing.

The group formed the Mendota Advanced Bioenergy Beet Cooperative and, in 2010, earned a $1.5 million state grant to measure the feasibility of the power plant project. The cooperative expects to learn this summer if it will receive a grant for construction of an operational pilot plant that converts sugar beets–a carbon-based feedstock–into advanced ethanol.

Farmer John Diener of Red Rock Ranch in Five Points, the founding president of the cooperative board, called the production of low-carbon-intensity transportation fuels a response by area farmers to the state”s new policy to reduce carbon emissions. Assembly Bill 32, the Global Warming Solutions Act, created an emissions trading market that allows regulated entities to use offsets as part of the state”s mandatory climate change program.

“We”re worried about AB 32 and how much it is going to cost us to implement that on our farms,” Diener said. “Green energy is one of the ways for us to do some offsets and keep the cost down, so that we can remain competitive.”

Jim Tischer, project consultant and regional program manager for California State University Center for Irrigation Technology, said the biorefinery would be an integrated facility where technology for producing green energy–anaerobic digesters, biomass gasifiers and the ethanol plant–would support each other.

“With an integrated facility like this, the trick is that everything has to run like a top where you have backups for each particular major element,” Tischer said. “It is beautiful when it goes well, because your carbon index is down, your economic impact is great, the farmers will make money and the communities benefit, as well.”

The energy beet refinery facility would incorporate:

n Advanced ethanol production: About 150 truckloads of harvested beets a day would be processed into advanced, second-level ethanol. During the process, some cellulosic ethanol would also be produced. Beets produce about 1,200 gallons per acre of ethanol, compared to 450 to 500 gallons per acre of corn. On an annual basis, 1.4 million tons of beets would be needed, which represents the production from about 35,000 acres.

n Anaerobic digester: Pulp material from the beets would go through the anaerobic digester and the process would yield biomethane. When scrubbed, it produces natural gas that can be used for transportation or injected into pipelines. The process also produces liquid fertilizer.

n Biomass gasifier: Biomass prunings would go into the biomass gasifier and into a steam turbine, which would make both steam and electricity. The processed steam would be recycled for ethanol production and the electricity would be used internally. The process would produce almost 40 percent of its own electricity.

n Water treatment facility: Wastewater from the beets and from the city of Mendota would be processed through the water treatment facility and converted into processed water. About 400 acre-feet of surplus water for agriculture and landscaping would be produced each year.

The cost to build the facility is estimated at $175 million. Annual economic activity that it is expected to bring to the area totals $120 million, and the addition of 100 local jobs.

“If this goes forward, it points in a direction where California agriculture can take a leadership role in developing transportation fuels internally in California,” Tischer said. “We keep those dollars here in our backyard. In Mendota, the unemployment rate is about 40 percent, so the $100 million-plus annual economic activity in the area will benefit the area.”

Farmer Bill Pucheu of Tranquillity, current chairman of the cooperative board, said he”s optimistic about the project.

“I”ve been very encouraged with how things have been developing,” he said.

A former Spreckels sugar beet grower, Pucheu used the beets as a rotation crop for cotton and other row crops.

“It would be nice to get beets back into our crop mix, if it works out economically, because it is a real nice rotation crop. Beets wouldn”t be a huge crop for us, but it is certainly an option that we”d like to have and that”s why I”ve been pursuing it,” he said.

Steve Kaffka, University of California statewide sugar beet specialist and director of the California Biomass Collaborative, said sugar beets are a good crop to convert to ethanol due to their high fiber content, and said the region features a year-round growing season.

“Beets can be produced year-round and the Europeans (who already produce ethanol from sugar beets) have developed self-propelled harvesters that traffic most soils,” Kaffka said. “These harvesters are amazing machines. They are fast and can pull beets out clean, even in moist, clay loam soils. It”s potentially very exciting and there”s no reason that these farmers can”t do this.”

Kaffka described additional benefits to growing beets.

“What is encouraging about beets is yields have been rising around the world fairly steadily over the last couple of decades and they continue to increase without increasing the inputs that are needed to produce them,” Kaffka said.

“The San Joaquin Valley is probably the most ideal environment to grow beets in the world. As such, we have the ability to grow beets all of the time,” Diener said.